Thermoplastic Vulcanizate PV Back Sheets

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Solution Overview

Problem

Conventional photovoltaic (PV) module back sheets are complex, costly, and prone to delamination, with higher rigidity that can lead to rupture and reduced flexibility, while alternative EPDM-based solutions face adhesion and processing challenges.

Innovation Solution

Thermoplastic vulcanizate (TPV) compositions with a crosslinked rubber phase dispersed in a continuous thermoplastic matrix, such as polypropylene, are used to form back sheets with specific hardness and modulus for improved flexibility and adhesion, potentially eliminating the need for additional encapsulant layers and allowing for non-planar geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional multi-layer back sheets are used, then protection against moisture ingress, mechanical deformation, and electrical charge loss is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveprotection against moisture ingress, mechanical deformation, and electrical charge lossVSAvoidmulti-layer construction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple protective functions (moisture barrier, mechanical strength, electrical insulation) into a single-layer thermoplastic vulcanizate back sheet, eliminating the need for separate multi-layer constructions while maintaining comprehensive protection

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses thermoplastic vulcanizate, a composite material consisting of crosslinked rubber particles dispersed in a thermoplastic matrix, to achieve multiple protective functions simultaneously in a single layer, replacing conventional multi-layer polymeric constructions

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional multi-layer back sheets are used, then protective functions are improved, but manufacturing cost increases

Engineering Contradiction:
Improveprotective functionsVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple protective functions into a single-layer thermoplastic vulcanizate back sheet, reducing the number of lamination steps and material layers required, thereby simplifying manufacturing and reducing costs

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts and consolidates the essential protective functions into a single material system (thermoplastic vulcanizate), eliminating redundant layers and reducing manufacturing complexity and cost

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If conventional multi-layer back sheets are used, then protection is improved, but risk of delamination increases

Engineering Contradiction:
ImproveprotectionVSAvoiddelamination resistance
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent combines all protective functions into a single homogeneous thermoplastic vulcanizate layer, eliminating the interfaces between multiple layers that serve as delamination pathways in conventional constructions

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The use of thermoplastic vulcanizate with its unique composite structure (crosslinked rubber in thermoplastic matrix) provides both protection and delamination resistance in a single integrated material without requiring multiple laminated layers

Inventive Principle:
Principle #40Composite materials

4Reliability

If conventional back sheets are used, then protection is improved, but flexibility and resistance to rupture are reduced

Engineering Contradiction:
ImproveprotectionVSAvoidflexibility and resistance to rupture
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs thermoplastic vulcanizate, a composite material where crosslinked rubber particles are dispersed in a thermoplastic matrix, providing both protective functions and enhanced flexibility with resistance to rupture

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameters by using thermoplastic vulcanizate with specific properties (crosslinked rubber content, thermoplastic matrix type) to achieve the desired balance between protection, flexibility, and rupture resistance

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

TPV-based back sheets enhance the durability and flexibility of PV modules, reduce manufacturing costs, and maintain or improve electrical insulation properties, while allowing for more efficient encapsulation and easier integration with PV cells, with improved resistance to environmental stressors like damp heat.

Implementation Method 1

a crosslinked rubber phase dispersed in a continuous thermoplastic matrix

Methodology Applied
Scientific EffectCrosslinking:

Implementation Method 2

crosslinked rubber phase dispersed in a continuous thermoplastic matrix

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 3

continuous thermoplastic matrix, such as polypropylene

Methodology Applied
Scientific EffectThermoplastic bonding:

Data Source

PatentEP3437143B1Thermoplastic vulcanizate compositions for photovoltaic cell applications
Publication Date: 2023.04.05 EXXONMOBIL CHEMICAL PATENTS INC
  • EP3437143B1 patent drawingFigure 1
  • EP3437143B1 patent drawingFigure 2a~2c
  • EP3437143B1 patent drawingFigure 2d

AI summary

Provided herein are back sheets comprising and/or otherwise made from thermoplastic vulcanizates, PV modules comprising such TPV-based back sheets, and methods for forming the TPV back sheets and PV modules. TPV-based back sheets provide particular advantages over incumbent back sheets, including increased flexibility, greater electrical insulation properties, and more desirable barrier properties. The TPV-based back sheets of some embodiments provide PV modules improved endurance, particularly under the changing and often harsh environmental conditions in which PV modules are often deployed. The TPV-based back sheets of some embodiments also enable efficient construction of unusual PV module geometries, such as non-planar (e.g., curved and/or hinged) geometries.